FreeBSD/Linux Kernel Cross Reference
sys/dev/iicbus/ad7418.c

     /*-
      * Copyright (c) 2006 Sam Leffler.  All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
      * 1. Redistributions of source code must retain the above copyright
      *    notice, this list of conditions and the following disclaimer.
      * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __FBSDID("$FreeBSD$");
    /*
     * Analog Devices AD7418 chip sitting on the I2C bus.
     */
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/lock.h>
    #include <sys/module.h>
    #include <sys/bus.h>
    #include <sys/resource.h>
    #include <sys/rman.h>
    #include <sys/sysctl.h>
    #include <sys/sx.h>
    
    #include <machine/bus.h>
    #include <machine/cpu.h>
    #include <machine/cpufunc.h>
    #include <machine/frame.h>
    #include <machine/resource.h>
    #include <machine/intr.h>
    
    #include <dev/iicbus/iiconf.h>
    
    #include "iicbus_if.h"
    
    #define IIC_M_WR        0       /* write operation */
    
    #define AD7418_ADDR     0x50    /* slave address */
    
    #define AD7418_TEMP     0       /* Temperature Value (r/o) */
    #define AD7418_CONF     1       /* Config Register (r/w) */
    #define AD7418_CONF_SHUTDOWN    0x01
    #define AD7418_CONF_CHAN        0xe0    /* channel select mask */
    #define AD7418_CHAN_TEMP        0x00    /* temperature channel */
    #define AD7418_CHAN_VOLT        0x80    /* voltage channel */
    #define AD7418_THYST    2       /* Thyst Setpoint (r/o) */
    #define AD7418_TOTI     3       /* Toti Setpoint */
    #define AD7418_VOLT     4       /* ADC aka Voltage (r/o) */
    #define AD7418_CONF2    5       /* Config2 Register (r/w) */
    
    struct ad7418_softc {
            device_t        sc_dev;
            struct sx       sc_lock;
            int             sc_curchan;     /* current channel */
            int             sc_curtemp;
            int             sc_curvolt;
            int             sc_lastupdate;  /* in ticks */
    };
    
    static void ad7418_update(struct ad7418_softc *);
    static int ad7418_read_1(device_t dev, int reg);
    static int ad7418_write_1(device_t dev, int reg, int v);
    
    static int
    ad7418_probe(device_t dev)
    {
            /* XXX really probe? */
            device_set_desc(dev, "Analog Devices AD7418 ADC");
            return (BUS_PROBE_NOWILDCARD);
    }
    
    static int
    ad7418_sysctl_temp(SYSCTL_HANDLER_ARGS)
    {
            struct ad7418_softc *sc = arg1;
            int temp;
    
            sx_xlock(&sc->sc_lock);
            ad7418_update(sc);
            temp = (sc->sc_curtemp / 64) * 25;
            sx_xunlock(&sc->sc_lock);
            return sysctl_handle_int(oidp, &temp, 0, req);
    }
   
   static int
   ad7418_sysctl_voltage(SYSCTL_HANDLER_ARGS)
   {
           struct ad7418_softc *sc = arg1;
           int volt;
   
           sx_xlock(&sc->sc_lock);
           ad7418_update(sc);
           volt = (sc->sc_curvolt >> 6) * 564 / 10;
           sx_xunlock(&sc->sc_lock);
           return sysctl_handle_int(oidp, &volt, 0, req);
   }
   
   static int
   ad7418_attach(device_t dev)
   {
           struct ad7418_softc *sc = device_get_softc(dev);
           struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(dev);
           struct sysctl_oid *tree = device_get_sysctl_tree(dev);
           int conf;
   
           sc->sc_dev = dev;
           sx_init(&sc->sc_lock, "ad7418");
   
           SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                   "temp", CTLTYPE_INT | CTLFLAG_RD, sc, 0,
                   ad7418_sysctl_temp, "I", "operating temperature");
           SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                   "volt", CTLTYPE_INT | CTLFLAG_RD, sc, 0,
                   ad7418_sysctl_voltage, "I", "input voltage");
   
           /* enable chip if configured in shutdown mode */
           conf = ad7418_read_1(dev, AD7418_CONF);
           if (conf >= 0 && (conf & AD7418_CONF_SHUTDOWN))
                   ad7418_write_1(dev, AD7418_CONF, conf &~ AD7418_CONF_SHUTDOWN);
   
           return (0);
   }
   
   static int
   ad7418_read_1(device_t dev, int reg) 
   {
           uint8_t addr = reg;
           uint8_t data[1];
           struct iic_msg msgs[2] = {
                { AD7418_ADDR, IIC_M_WR, 1, &addr },
                { AD7418_ADDR, IIC_M_RD, 1, data },
           };
           return iicbus_transfer(dev, msgs, 2) != 0 ? -1 : data[0];
   }
   
   static int
   ad7418_write_1(device_t dev, int reg, int v) 
   {
           /* NB: register pointer precedes actual data */
           uint8_t data[2];
           struct iic_msg msgs[1] = {
                { AD7418_ADDR, IIC_M_WR, 2, data },
           };
           data[0] = reg;
           data[1] = v & 0xff;
           return iicbus_transfer(dev, msgs, 1);
   }
   
   static void
   ad7418_set_channel(struct ad7418_softc *sc, int chan)
   {
           if (sc->sc_curchan == chan)
                   return;
           ad7418_write_1(sc->sc_dev, AD7418_CONF, 
               (ad7418_read_1(sc->sc_dev, AD7418_CONF) &~ AD7418_CONF_CHAN)|chan);
           sc->sc_curchan = chan;
   #if 0
           /*
            * NB: Linux driver delays here but chip data sheet
            *     says nothing and things appear to work fine w/o
            *     a delay on channel change.
            */
           /* let channel change settle, 1 tick should be 'nuf (need ~1ms) */
           tsleep(sc, 0, "ad7418", hz/1000);
   #endif
   }
   
   static int
   ad7418_read_2(device_t dev, int reg) 
   {
           uint8_t addr = reg;
           uint8_t data[2];
           struct iic_msg msgs[2] = {
                { AD7418_ADDR, IIC_M_WR, 1, &addr },
                { AD7418_ADDR, IIC_M_RD, 2, data },
           };
           /* NB: D15..D8 precede D7..D0 per data sheet (Fig 12) */
           return iicbus_transfer(dev, msgs, 2) != 0 ?
                   -1 : ((data[0] << 8) | data[1]);
   }
   
   static void
   ad7418_update(struct ad7418_softc *sc)
   {
           int v;
   
           sx_assert(&sc->sc_lock, SA_XLOCKED);
           /* NB: no point in updating any faster than the chip */
           if (ticks - sc->sc_lastupdate > hz) {
                   ad7418_set_channel(sc, AD7418_CHAN_TEMP);
                   v = ad7418_read_2(sc->sc_dev, AD7418_TEMP);
                   if (v >= 0)
                           sc->sc_curtemp = v;
                   ad7418_set_channel(sc, AD7418_CHAN_VOLT);
                   v = ad7418_read_2(sc->sc_dev, AD7418_VOLT);
                   if (v >= 0)
                           sc->sc_curvolt = v;
                   sc->sc_lastupdate = ticks;
           }
   }
   
   static device_method_t ad7418_methods[] = {
           DEVMETHOD(device_probe,         ad7418_probe),
           DEVMETHOD(device_attach,        ad7418_attach),
   
           {0, 0},
   };
   
   static driver_t ad7418_driver = {
           "ad7418",
           ad7418_methods,
           sizeof(struct ad7418_softc),
   };
   static devclass_t ad7418_devclass;
   
   DRIVER_MODULE(ad7418, iicbus, ad7418_driver, ad7418_devclass, 0, 0);
   MODULE_VERSION(ad7418, 1);
   MODULE_DEPEND(ad7418, iicbus, 1, 1, 1);

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